Feb 24, 2010 · Ospho is a water-based solution and the water can hide in nooks and crannies causing adhesion failure of the primer. Old car frames are particularly susceptible to this because of the …

Mar 30, 2010 · This is the start of a thread dedicated to successful rust removal using ospho,a water based phosphric acid product I've been using professionally for many years. Ospho has some …

Oct 10, 2015 · I just completed a crude rust removal experiment and wanted to share my results with everyone. 3 products were tested: - Ospho ($32/gal) - Eastwood’s Gel Rust Dissolver ($38/gal) - …

Nov 21, 2023 · Meaning after you have treated it with Ospho which will take a while to get all the surface rust off and etch a tooth into the metal. Re-wet it with Ospho and keep it wet with Ospho for 10-15 …

May 15, 2015 · Ospho, is a great product for automotive if used right, we give scare warnings because we want people to call so we can make sure they know how to neutralize it, so no problems will arise.

Apr 23, 2004 · I have been treating my bare metal with ospho before putting my bondo on and have been having problems with the bondo lifting. Should I be rinsing the ospho off or should I leave it on? …

Jul 18, 2025 · I have read and understand Barry’s recommended procedure for neutralizing Ospho prior to spraying epoxy primer. I have also read that Ospho is SPI’s only (and begrudgingly) …

Sep 9, 2022 · My understanding is that Ospho will convert surface rust, but if the rust layer isn't very superficial, I would assume that under the ospho treatment there is still deep rust. Is that just …

Sep 8, 2024 · At this point I would do as texasking suggested, but for anyone else using ospho, I use ZEP industrial degreaser to wash the thoroughly wet acid off, then rinse with water.

Aug 23, 2025 · Flash rust means the Ospho is neutrized in that area. I think it happens because of hard water. The iron in it. The not rusted spots might mean it's not neutralized in those areas IDK for sure. …